(QHA) -

U.S. Secretary of State John Kerry met with Russian Foreign Minister Sergei Lavrov in Geneva on March 2 to discuss Ukrainian crisis and the Feb 27 killing of Russia’s top opposition leader, former Prime Minister Boris Nemtsov.

Kerry and Lavrov shook hands but made no public remarks before they began talks on the sidelines of the UN Human Rights Council in Geneva.

Kerry on March 1 called for a "thorough, transparent, real investigation" into Nemtsov's killing as tens of thousands marched through Moscow to mourn his death.

In Ukraine, a drop in violence and moves by Ukrainian forces and pro-Russia rebels to withdraw heavy weapons from the front line had raised hopes a shaky two-week-old cease fire could hold.

But Ukraine's military warned on March 1 the rebels were using the truce to regroup for new attacks on government positions.

A spokesman named as major targets government-held Mariupol, a strategic port city, and Artemivsk, north of the rebel stronghold of Donetsk.